Prevent 'NotAllowedError' and 'user didn't interact with the document first' errors for Vimeo embedded in WordPress. No longer needed in WP 5.3 beta 3 or higher.

readme.txt

Add the code in the functions.php file below to your active theme's functions.php file.

You can remove the code once WordPress updates to media element 4.2.10+. (WordPress 5.3 beta 3 updated from 4.2.6 to 4.2.13: https://wordpress.org/news/2019/10/wordpress-5-3-beta-3/)

functions.php

add_action( 'wp_enqueue_scripts', 'studiopress_load_newer_vimeo_mediaelement', 100 );
/**
 * Replace the mediaelement-vimeo script with a newer version.
 *
 * This works around an issue in WordPress core that can prevent playback of
 * Vimeo videos embedded via the `wp_video_shortcode()` function.
 *
 * This is caused by WordPress loading an older version of the Vimeo script
 * (currently loads 4.2.6), which does not add the 'allow=autoplay'
 * attribute to iframes that Chrome now requires to permit video playback as
 * the first user action on a page.
 *
 * See https://github.com/mediaelement/mediaelement/issues/2618.
 *
 * This code and the `add_action` line above could be removed once WordPress
 * updates to use Media Element 4.2.10+.
 */
function studiopress_load_newer_vimeo_mediaelement() {
	wp_dequeue_script( 'mediaelement-vimeo' );
	wp_deregister_script( 'mediaelement-vimeo' );

	wp_enqueue_script(
		'mediaelement-vimeo',
		'https://cdn.jsdelivr.net/gh/mediaelement/mediaelement@4.2.10/src/js/renderers/vimeo.js',
		array( 'mediaelement' ),
		'4.2.10',
		1
	);
}